Settings → Cosmetic's theme picker showed only the theme name. Now
each chip carries a small Ace-of-Spades + back preview pair so the
player can see what each theme looks like before switching.
A new ThemeThumbnailCache resource keys per-theme by id and stores
two Handle<Image>s (ace + back) rasterised at thumbnail resolution
via the existing rasterize_svg path. Generation runs once per
theme registration in theme_plugin; subsequent picker re-spawns
just look up the cached handles. Themes that lack one of the
preview SVGs (broken user theme) get a Handle::default() placeholder
rather than crashing — the placeholder renders as a transparent
rectangle the same size as the missing thumbnail.
The picker chip spawn loop in settings_plugin reads the cache and
renders the pair as two child sprites above the chip text. The
selected-theme chip's existing STATE_SUCCESS tint sits behind the
thumbnails; contrast stays readable.
Asset-source plumbing in assets/sources.rs and assets/mod.rs picks
up the new bytes-loading helper that the thumbnail generator uses
for embedded:// theme assets at startup time (before AssetServer is
fully initialised).
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
funman300
ba527de351